assume cs:codesg

codesg segment

        mov ax, 4c00h
        int 21h

start:	mov ax,0
		
s:		nop  					
        nop
        mov di, offset s  
        mov si, offset s2
        mov ax, cs:[si]
        mov cs:[di], ax

s0:     jmp short s				
 
s1:		mov ax, 0				
        int 21h
        mov ax, 0
 
s2:		jmp short s1			
        nop
 
codesg ends

end start

